#!/usr/bin/env node
// Verifies the production build: every route has prerendered HTML with its own
// canonical and og:url, the CSR shell exists, and no Google font host is left.

import { existsSync, readFileSync, readdirSync } from 'node:fs';
import { join, dirname } from 'node:path';
import { fileURLToPath } from 'node:url';

const root = join(dirname(fileURLToPath(import.meta.url)), '..');
const distDir = join(root, 'dist', 'playground-frontend', 'browser');
const ORIGIN = 'https://andreas-dahm.eu';
const FORBIDDEN_HOSTS = ['fonts.googleapis.com', 'fonts.gstatic.com'];

function* walk(dir) {
  for (const entry of readdirSync(dir, { withFileTypes: true })) {
    const path = join(dir, entry.name);
    if (entry.isDirectory()) {
      yield* walk(path);
    } else {
      yield path;
    }
  }
}

function routePaths() {
  const constants = readFileSync(join(root, 'src', 'app', 'constants', 'RouterConstants.ts'), 'utf8');
  const paths = [...constants.matchAll(/PATH: '([^']+)'/g)].map(match => match[1]);
  return ['', ...paths];
}

function checkRoute(route, failures) {
  const file = join(distDir, route, 'index.html');
  if (!existsSync(file)) {
    failures.push(`missing ${file}`);
    return;
  }
  const html = readFileSync(file, 'utf8');
  const url = `${ORIGIN}/${route}`;
  const label = route || '/';
  if (!html.includes(`rel="canonical" href="${url}"`) && !html.includes(`href="${url}" rel="canonical"`)) {
    failures.push(`${label}: canonical is not ${url}`);
  }
  if (!html.includes(`property="og:url" content="${url}"`) && !html.includes(`content="${url}" property="og:url"`)) {
    failures.push(`${label}: og:url is not ${url}`);
  }
  if (!/<title>[^<]+<\/title>/.test(html)) {
    failures.push(`${label}: empty <title>`);
  }
}

function checkForbiddenHosts(failures) {
  for (const file of walk(distDir)) {
    const content = readFileSync(file, 'latin1');
    for (const host of FORBIDDEN_HOSTS) {
      if (content.includes(host)) {
        failures.push(`${file} references ${host}`);
      }
    }
  }
}

if (!existsSync(distDir)) {
  console.error(`Build output not found: ${distDir}`);
  process.exit(1);
}

const failures = [];
routePaths().forEach(route => checkRoute(route, failures));
if (!existsSync(join(distDir, 'index.csr.html'))) {
  failures.push('missing index.csr.html');
}
checkForbiddenHosts(failures);

if (failures.length > 0) {
  console.error(`Prerender check failed:\n${failures.join('\n')}`);
  process.exit(1);
}
console.log('Prerender check passed.');